1. Field of the Invention
The present invention relates generally to the field of hand tools. More specifically the present invention relates to eccentric rotary pliers for gripping an object with tremendous mechanical advantage and having a long reach into a tight space with virtually undiminished gripping force. The pliers include a shaft guide structure preferably in the form of a guide tube having a tube proximal end connected to a radially protruding tube rotation lever and having a tube distal end with a distally protruding plier outer jaw radially spaced from the guide tube longitudinal axis, and includes a torque transmission shaft rotatably retained within the guide tube having a shaft proximal end connected to a radially protruding shaft rotation lever adjacent to the tube rotation lever and having a shaft distal end with a plier inner jaw circumferentially aligned with the plier outer jaw, such that rotation of the torque transmission shaft relative to the guide tube by pivoting the tube rotation lever and shaft rotation lever relative to each other rotates the plier inner jaw along a circumferential path either toward or away from abutment with the plier outer jaw to grip or release an object between plier inner and outer jaws. The large ratio of the radial distance from the shaft rotational axis to the jaws and to the gripped region of the lever gives the pliers a very great mechanical advantage, on the order of 80 to 1, or 80 pounds gripping force between the inner and outer jaws for each pound of gripping force applied to the lever.
2. Description of the Prior Art
Conventional pliers include two elongate members pivoting in their middle regions about an interconnecting bolt which define plier jaws at member distal ends and plier handles at member proximal ends. A problem with these prior pliers is that they typically give a mechanical advantage of no more than five to one, and more typically of one two or three to one. Another problem has been that conventional pliers have a limited reach along a narrow path which cannot be extended in a practical way, limiting their usefulness when working on a vehicle engine and in many other applications.
It is thus an object of the present invention to provide eccentric rotary pliers which can provide a mechanical advantage of dozens of pounds of pliers gripping force to each pound of user hand gripping force.
It is another object of the present invention to provide such eccentric rotary pliers which can be designed to reach up to several feet along a narrow path with negligible loss in mechanical advantage, and may be used to feed wire into a distant opening.
It is still another object of the present invention to provide such eccentric rotary pliers which are compact and can be carried in most tool boxes, in a belt or in a holster.
It is finally an object of the present invention to provide such eccentric rotary pliers which are durable, reliable and relatively inexpensive to manufacture.